The operation of machining the impressionA cavity, or series of cavities (multiple), machined into a forging die to produce a desired configuration in the workpiece during forging. of a desired forgingThe process of working metal to a desired shape by impact or pressure in hammers, forging machines (upsetters), presses, rolls, and related forming equipment. into die blocksThe metal blocks into which forging impressions are machined and from which forgings are produced..